Lubricating oil supply apparatus of reciprocating compressor

ABSTRACT

A lubricating oil supply apparatus of a reciprocating compressor comprises: an oil cylinder penetratingly-formed at a lower side of a frame, for supporting a compression unit which compresses a fluid; an oil piston reciprocatingly-inserted into the oil cylinder and reciprocated by a vibration of the compressor, for pumping lubricating oil; a spring connected to a rear side of the oil piston and providing an elastic force to the oil piston; and a valve assembly disposed at a front side of the frame, for opening and closing a passage of lubricating oil supplied to a sliding part of the compressing unit. A dead volume existing at the oil supply apparatus is reduced thereby to smoothly supply lubricating oil even at the time of an initial driving that requires less pumping amount, thereby enhancing a lubricating performance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lubricating oil supply apparatus of areciprocating compressor, and more particularly, to a lubricating oilsupply apparatus of a reciprocating compressor capable of enhancing anoil supply performance and reducing a fabrication cost by reducing thenumber of components.

2. Description of the Conventional Art

Generally, a compressor is divided into a rotary compressor, areciprocating compressor, a scroll compressor, and etc. according to afluid compression method.

FIG. 1 is a sectional view of a reciprocating compressor in accordancewith the conventional art.

The conventional reciprocating compressor comprises: a case 106 to whicha suction pipe 102 and a discharge pipe 104 are connected and containinglubricating oil at a lower portion thereof; a reciprocating motor 108disposed in the case 106 for generating a reciprocation force; acompressing unit 110 for compressing a fluid by receiving thereciprocation force generated from the reciprocating motor 108; frames112, 114, and 116 for supporting the reciprocating motor 108 and thecompressing unit 110; a lubricating oil supply apparatus for supplyinglubricating oil contained in the case 106 to each frictional part of thecompressor; and etc.

The reciprocating motor 108 includes: an outer stator 118 having acylindrical shape and on which a winding coil to which a power isapplied is wound; an inner stator 120 disposed at an innercircumferential surface of the outer stator 118 with a certain air gap;and a magnet 124 disposed between the outer stator 118 and the innerstator 120 with a certain interval for performing a linear reciprocationwhen a power is applied to the winding coil 122.

The magnet 124 is fixed to an outer circumferential surface of a magnetholder 126 with the same interval, and the magnet holder 126 isintegrally formed with a piston 128 of the compressing unit 110.

A first resonant spring 134 and a second resonant spring 136 arerespectively disposed between one side surface of the magnet holder 126and the frame 112 and between another side surface of the magnet holder126 and the frame 116, thereby inducing a resonant movement of thepiston 128.

The compressing unit 110 is constituted with the piston 128 connected tothe magnet holder 126 and linearly reciprocated, a cylinder 142 to whichthe piston 128 is slidably inserted and forming a certain compressionchamber 140, a suction valve 146 for opening and closing an inletmounted at the front side of the piston 128, and a discharge valveassembly 148 mounted at the front side of the cylinder 142 fordischarging a compressed fluid to outside when a pressure inside thecompression chamber 140 is more than a preset pressure.

The discharge valve assembly 148 includes: a discharge valve 150 adheredto the front side surface of the cylinder 142 for discharging acompressed fluid; a discharge cover 152 mounted at the front side of thecylinder 142 and to which the discharge valve 104 for discharging afluid is connected; and a spring 154 disposed between the inner sidesurface of the discharge cover 152 and the discharge valve 150 forelastically supporting the discharge valve 150.

The frames include: a first frame 112 to which the outer circumferentialsurface of the cylinder 142 is fixed, for fixing the front side of thereciprocating motor 108; a second frame 114 for supporting the rear sideof the reciprocating motor 108; and a third frame 116 coupled to thesecond frame 114 for supporting the second resonant spring 136.

The lubricating oil supply apparatus for supplying lubricating oilcontained at the lower portion of the case 106 to a sliding part betweenthe cylinder 142 and the piston 128 includes: a pumping unit 160 fixedat one side of the first frame 112, for pumping lubricating oil by usingvibration generated at the time of driving the compressor; a valveassembly 164 for opening and closing a passage of lubricating oil pumpedby the pumping unit 160; and a lubricating oil supply passage 166 formedat the first frame 112 for supplying lubricating oil to the sliding partbetween the cylinder 142 and the piston 128.

The pumping unit 160 includes: an oil cylinder 170 fixed at a lowerportion of the first frame 112; an oil piston 172 disposed in the oilcylinder 170 to be linearly movable and reciprocated by a vibration ofthe compressor, for pumping lubricating oil; and springs 174 and 176 forelastically supporting both sides of the oil piston 172.

The valve assembly 164 includes: an oil cover 182 mounted at the frontside of the first frame 112 and provided with a lubricating oil passage180 therein, the lubricating oil passage 180 through which lubricatingoil passes; a suction valve 184 disposed in the oil cover 182 foropening and closing an inlet through which the lubricating oil issucked; a discharge valve 186 disposed in the oil cover 182 for openingand closing an outlet through which the compressed lubricating oil isdischarged; and a suction pipe 188 mounted at the oil cover 182 forsucking lubricating oil contained at the lower portion of the case 106.

The first frame 112 is provided with a lubricating oil hole 190connected to the oil cylinder 170 for sucking and discharginglubricating oil.

FIGS. 2A and 2B are sectional views showing an operational state of alubricating oil supply apparatus of the reciprocating compressor inaccordance with the conventional art;

Operation of the conventional lubricating oil supply apparatus of thereciprocating compressor will be explained.

As shown in FIG. 2A, once the oil piston 172 is retreated by a vibrationgenerated when the compressor is driven, a suction pressure isgenerated. By the suction pressure, the suction valve 184 is opened andlubricating oil is sucked through the suction pipe 188. The lubricatingoil is introduced into the oil cylinder 170 through the lubricating oilhole 190 formed at the first frame 112.

Then, as shown in FIG. 2B, when the oil piston 172 advances by avibration generated when the compressor is driven and thereby thelubricating oil contained in the cylinder 170 is discharged through thelubricating oil hole 190, the suction valve 184 is closed and thedischarge valve 186 is opened. According to this, the lubricating oil issupplied to the sliding part between the cylinder 142 and the piston 128through the lubricating oil supply passage 166 thus to perform alubricating operation.

However, in the conventional lubricating oil supply apparatus of thereciprocating compressor, the lubricating oil hole 190 for suckinglubricating oil into the oil cylinder 170 and discharging out is formedat the first frame 112, and a space for installing the spring 174 at thefront side of the oil piston 172 is required. Therefore, the lubricatingoil hole 190 and the installation space of the spring 174 become a deadvolume. By the dead volume, in case that a vibration amount is less, forexample, at the time of an initial driving of the compressor,lubricating oil is not smoothly supplied to the sliding part and therebya friction is generated at the sliding part of the compressing unit.

Additionally, in the conventional lubricating oil supply apparatus ofthe reciprocating compressor, the pumping unit 160 for pumpinglubricating oil has a great number of components and complicatedstructure and assembly processes, thereby increasing a fabrication cost.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide alubricating oil supply apparatus of a reciprocating compressor capableof enhancing a lubricating performance by reducing a dead volumeexisting at an oil supply apparatus and thus by smoothly supplyinglubricating oil even at the time of an initial driving that requiresless pumping amount.

Another object of the present invention is to provide a lubricating oilsupply apparatus of a reciprocating compressor capable of enhancing anassembly characteristic and reducing a fabrication cost by simplifying astructure of a pumping unit for pumping lubricating oil.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided a lubricating oil supply apparatus of a reciprocatingcompressor comprising: an oil cylinder penetratingly formed at a lowerside of a frame, for supporting a compression unit which compresses afluid; an oil piston reciprocatingly inserted into the oil cylinder andreciprocated by a vibration of the compressor, for pumping lubricatingoil; a spring connected to the rear side of the oil piston and providingan elastic force to the oil piston; and a discharge valve assemblydisposed at the front side of the frame for opening and closing apassage of lubricating oil supplied to a sliding part of the compressingunit.

The oil cylinder is penetratingly formed at a lower side of the frame ina longitudinal direction of the compressor, and is positioned to behigher than a surface of lubricating oil contained at a lower portion ofthe compressor case.

The oil piston is disposed to be protruded towards a rear side of theoil cylinder.

The spring is formed as a plate spring, of which one side is connectedto a rear side of the oil piston and another side is connected to theframe.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a sectional view of a reciprocating compressor in accordancewith the conventional art;

FIGS. 2A and 2B are sectional views showing an operational state of alubricating oil supply apparatus of the reciprocating compressor inaccordance with the conventional art;

FIG. 3 is a sectional view of a reciprocating compressor according toone embodiment of the present invention; and

FIGS. 4A and 4B are sectional views showing an operational state of alubricating oil supply apparatus of a reciprocating compressor accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

Hereinafter, one embodiment of a reciprocating compressor according tothe present invention will be explained with reference to attacheddrawings.

Even though a plurality of preferred embodiments of the reciprocatingcompressor according to the present invention can exist, the mostpreferred embodiment will be explained.

FIG. 3 is a sectional view of a reciprocating compressor according toone embodiment of the present invention.

The reciprocating compressor according to the present inventioncomprises: a case 6 of a certain hermetic space to which a suction pipe2 for sucking a fluid and a discharge pipe 4 for discharging acompressed fluid are connected and containing lubricating oil at a lowerportion thereof; a reciprocating motor 8 disposed in the case 6 forgenerating a reciprocation force when a power is applied; a compressingunit 10 for compressing a fluid by receiving the reciprocation forcegenerated from the reciprocating motor 8; frames 12, 14, and 16 forsupporting the reciprocating motor 8 and the compressing unit 10; and alubricating oil supply apparatus for supplying lubricating oil containedin the lower portion of the case 6 to a sliding part of the compressor10.

The reciprocating motor 8 includes: an outer stator 18 of a cylindricalshape; an inner stator 20 disposed at an inner circumferential surfaceof the outer stator 18 with a certain air gap; a winding coil 22 woundeither on the outer stator 18 or on the inner stator 20, for generatinga flux between the outer stator 18 and the inner stator 20 when a poweris applied; and a magnet 24 reciprocatingly disposed at the air gapbetween the outer stator 18 and the inner stator 20.

The magnet 24 is fixed to an outer circumferential surface of a magnetholder 26 with the same interval, and the magnet holder 26 is integrallyformed with a piston 30 of the compressing unit 10.

A first resonant spring 48 and a second resonant spring 50 arerespectively disposed between one side surface of the magnet holder 26and the frame 12 and between another side surface of the magnet holder26 and the frame 16, thereby inducing a resonant movement of the piston30.

The compressing unit 10 is constituted with the piston 30 connected tothe magnet holder 26 and reciprocated, a cylinder 34 into which thepiston 30 is slidably inserted and forming a certain compression chamber32, a suction valve 38 for opening and closing an inlet mounted at thefront side of the piston 30, and a discharge valve assembly 36 mountedat the front side of the cylinder 34 for discharging a compressed fluidto outside when a pressure inside the compression chamber 32 is morethan a preset pressure.

The discharge valve assembly 36 includes: a discharge valve 40 whichcomes in contact with the front side surface of the cylinder 34 andopens/closes an outlet through which a compressed fluid is discharged; adischarge cover 42 mounted at the front side of the cylinder 34 and towhich the discharge valve 4 is connected; and a spring 44 disposedbetween the inner side surface of the discharge cover 42 and thedischarge valve 40 for elastically supporting the discharge valve 40.

The frames include: a first frame 12 fixed to an outer circumferentialsurface of the cylinder 34 and supporting one side surface of thereciprocating motor 8; a second frame 14 for supporting another sidesurface of the reciprocating motor 8; and a third frame 16 forsupporting the second resonant spring 50.

The lubricating oil supply apparatus includes: a pumping unit 50 fixedat lower side of the first frame 12, for pumping lubricating oil byusing a vibration generated at the time of driving the compressor; anoil valve assembly 52 for opening and closing a passage of lubricatingoil pumped by the pumping unit 50; and a lubricating oil supply passage54 formed at the first frame 12 for supplying lubricating oil to asliding part between the cylinder 34 and the piston 30.

The pumping unit 50 includes: an oil cylinder 56 penetratingly formed ata lower portion of the first frame 12; an oil piston 58 linear-movablyinserted into the oil cylinder 56 and reciprocated by a vibration of thecompressor, for pumping lubricating oil; and an oil spring 60 connectedto a rear surface of the oil piston 58, for elastically supporting theoil piston 58.

The oil cylinder 56 is penetratingly formed at a lower side of the firstframe 12 in a longitudinal direction of the compressor, and ispositioned to be higher than a surface of lubricating oil contained inthe lower portion of the case 6. The reason why the oil cylinder 56 ispositioned to be higher than the surface of the lubricating oil is tomake the oil cylinder 56 not be soaked in the lubricating oil sincenoise and vapor are generated when the frames 12, 14, and 16 having widesurface areas come in contact with the lubricating oil.

The oil piston 58 is linear-movably inserted into the oil cylinder 56,and is disposed to be protruded towards the rear side of the first frame12 with a certain length.

One side of the oil spring 60 is connected to the oil piston 58 andanother side thereof is connected to the first frame 12, therebyproviding an elastic force to the oil piston 58 when the oil piston 58is reciprocated.

The oil spring 60 is preferably formed as a plate spring.

The oil valve assembly 52 includes: an oil cover 72 mounted at the frontside of the first frame 12 and provided with a lubricating oil passage70 therein, the lubricating oil passage 70 through which lubricating oilpasses; an oil suction valve 74 disposed in the oil cover 72 for openingand closing an inlet through which the lubricating oil is sucked; an oildischarge valve 76 disposed in the oil cover 72 for opening and closingan outlet through which the compressed lubricating oil is discharged;and a suction pipe 78 mounted at the oil cover 72 for suckinglubricating oil contained at the lower portion of the case 6.

FIGS. 4A and 4B are sectional views showing an operational state of alubricating oil supply apparatus of a reciprocating compressor accordingto the present invention.

Operation of the lubricating oil supply apparatus according to thepresent invention will be explained as follows.

As shown in FIG. 4A, once the oil piston 58 is retreated in the oilcylinder 56 formed at the first frame 12 by a vibration generated whenthe compressor is driven, a suction pressure is generated. By thesuction pressure, the oil suction valve 74 is opened and lubricating oilis sucked into the oil cylinder 56 through the suction pipe 78.

Then, as shown in FIG. 4B, when the oil piston 58 advances by avibration generated when the compressor is driven and thereby thelubricating oil contained in the oil cylinder 56 is discharged.According to this, the oil suction valve 74 is closed and the oildischarge valve 76 is opened, so that the lubricating oil is supplied tothe sliding part between the cylinder 34 and the piston 30 through thelubricating oil supply passage 54 thus to perform a lubricatingoperation.

In the lubricating oil supply apparatus of the reciprocating compressoraccording to the present invention, the oil cylinder is formed at thefirst frame and thereby the oil cylinder and the lubricating oil passageformed in the oil cover are directly connected to each other. Also, thespring disposed at the front side of the oil piston is removed thus tominimize a dead volume. According to this, lubricating oil can besmoothly supplied even when a lubricating oil pumping amount is less,for example, at the time of an initial driving of the compressor.

Additionally, the oil cylinder is directly formed at the first frame andthe spring is provided only at the rear side of the oil piston thus tosimplify a construction of the pumping unit, thereby reducing the numberof components, enhancing an assembly characteristic, and reducing afabrication cost.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. A lubricating oil supply apparatus of a reciprocating compressor comprising: an oil cylinder penetratingly-formed at a lower side of a frame, for supporting a compression unit which compresses a fluid; an oil piston reciprocatingly-inserted into the oil cylinder and reciprocated by a vibration of the compressor, for pumping lubricating oil; a spring connected to a rear side of the oil piston and providing an elastic force to the oil piston; and a valve assembly disposed at a front side of the frame, for opening and closing a passage of lubricating oil supplied to a sliding part of the compressing unit.
 2. The apparatus of claim 1, wherein the oil cylinder is penetratingly-formed at a lower side of the frame in a longitudinal direction of the compressor,
 3. The apparatus of claim 1, wherein the oil cylinder is positioned to be higher than a surface of lubricating oil contained at a lower portion of the compressor case.
 4. The apparatus of claim 1, wherein the oil piston is disposed to be protruded towards a rear side of the oil cylinder.
 5. The apparatus of claim 1, wherein one side of the spring is connected to a rear side of the oil piston and another side thereof is connected to the frame.
 6. The apparatus of claim 5, wherein the spring is formed as a plate spring. 